On Fri, 2002-03-29 at 13:38, Phil Williams wrote:
> >
> > A "proto_node" contains a "field_info" pointer; a "field_info", as
> > defined in <epan/proto.h>, contains:
> >
> > a "header_field_info" pointer;
> >
> > an "fvalue_t" pointer;
> >
> > a bunch of other information.
> >
> > The "header_field_info" structure points to a structure that represents
> > an attribute; the "fvalue_t" pointer points to a structure that
> > represents a value.
> >
> > The only problem is that the attributes are identified by
> > "header_field_info" pointers rather than by name. If we provided
> > routines to look up "header_field_info" structures by name, that
> > probably wouldn't be a problem.
> >
>
> Well in this case, can I not get access to the data I require by looking
> up using header_field_info pointers, rather than names?
> With the tree being (attribute, value), is the attribute (eg for TCP
> header length) always the same? If so wouldn't it be possible to
> get access to the data that I require? Though this is less elegant than
> using the actual names should it be feasible?
> If so, what values / names do these header_field_info pointers take?
>
Let's say we add a new function,
int
proto_registar_lookup_abbrev(const char*)
Then you could find the ID via:
tcp_hdr_len_id = proto_registar_lookup_abbrev("tcp.hdr_len")
With that, you could get an array of field_info pointers, since
a proto_tree might have more than 1 such field_info, via:
GPtrArray*
proto_get_finfo_ptr_array(proto_tree *tree, int id)
Then you could iterate across the array. For each field_finfo, you could
get the integer value via:
fvalue_get_integer(finfo_ptr->value);
--gilbert
